Luer connector assembly

ABSTRACT

A luer connector assembly is provided for enhancing the frictional engagement between medical devices such as syringes and needle assemblies. The assembly needle includes a female luer fitting having a passageway and a relatively soft, resilient member bounding the passageway. The passageway is also bounded by the body of the fitting, which is harder than the soft, resilient member. A male luer fitting inserted into the passageway engages both the soft, resilient member and the body of the female luer fitting. A method of manufacturing such a connector assembly is further provided. A first material is injected into a mold to form the body of a female luer fitting, the fitting including a passageway and a recess extending into the body. A second material is then injected such that it extends into the recess and bounds the passageway. The second material, when cool, is softer than the first material.

RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 10/485,082 filed Jan. 26, 2004, now abandoned, which is a 371 ofApplication No. PCT/US02/15888 filed May 21, 2002, which claims thebenefit of U.S. Application Ser. No. 60/308,380 filed Jul. 27, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The field of the invention relates to luer connector assemblies, andmethods for manufacturing such assemblies.

2. Brief Description of the Prior Art

Generally speaking, a hypodermic syringe consists of a cylindricalbarrel, most commonly made of thermoplastic material or glass, with adistal end adapted to be connected to a hypodermic needle and a proximalend adapted to receive a stopper and plunger rod assembly. One of thepurposes of the stopper is to provide a relatively air tight sealbetween itself and the syringe barrel so that movement of the stopper upand down the barrel will cause fluids to be drawn into or forced out ofthe syringe through the distal end. The stopper is moved along thesyringe barrel by applying axial force on a rigid plunger rod which isconnected to the stopper and is sufficiently long to be accessibleoutside of the barrel.

Hypodermic needle assemblies, typically including a cannula and a hub,are often times removably attached to syringes for performing a varietyof tasks such as the delivery of medication into patients and intodevices, and for withdrawing fluid samples from patients and from fluidsources. Usually, the hub of the hypodermic needle assembly has atapered interior surface adapted to engage the tapered tip of thesyringe barrel so that the two components are joined in a frictionalinterference fit. The tapered syringe tip and the complementary taperedreceptacle in the hub are referred to as standard luer fittings. A widevariety of other devices such as stopcocks and tubing sets have standardluer fittings which allow them to be engaged to a syringe tip.

It is important that the frictional fit between the syringe tip and theneedle hub or other device is strong enough to prevent accidentaldisengagement caused by the fluid pressures within the syringe and/orother factors. If the syringe tip becomes disengaged from the otherfluid delivery means, medications, blood or other fluids will be lostand there is also potential for contamination of the fluid.

To improve the strength of the interference fit between the syringe tipand the fluid delivery device, such as a hypodermic needle, many priorart devices, such as a hypodermic syringe, provide a circular internallythreaded receptacle which is concentric to and larger than the luer tipof the syringe barrel. The hypodermic needle or other fitting used withthis type of syringe has wings projecting radially outwardly from thebase of the needle hub so that the needle hub may be placed on thesyringe tip and rotated in a clockwise direction until the hub wingsengage the threads at the syringe tip and pull the needle hub into tightfrictional engagement with the syringe tip. This type of fitting iscommonly referred to as a luer lock. With a plastic syringe barrel thethreaded luer lock collar can be molded integrally with the syringebarrel as taught in U.S. Pat. No. 3,402,713 to Senkowski et al. Whenusing a glass syringe barrel the threaded collar is usually made of arelatively expensive metal part which is chrome plated and attached tothe glass syringe. Such a device is taught in U.S. Pat. No. 2,711,171 toDunnican. The type of device taught by Dunnican is commonly found onreusable glass syringes. However, its relative expense makes itimpractical for a disposable syringe assembly.

It is known to blast the tip of a glass syringe with abrasive particles,such as aluminum oxide beads or sand, to increase the roughness of thetip and, therefore, the strength of the frictional interference fitbetween the syringe tip and the needle hub. The roughened surface alsois believed to be helpful in the event that liquid is accidentallydeposited on the syringe tip, because the roughened surface is betterable to break through the liquid film as the needle hub is engagedthereon. A disadvantage of abrasive blasting a syringe tip to obtain aroughened surface is that the debris created by the blasting processmust be thoroughly and completely removed from the syringe barrel. Thiscleanup operation is an expensive secondary operation which is requiredbecause of the medical uses most syringes are placed in.

U.S. Pat. No. 5,312,377 discloses male and female luer members that arecomprised of soft, resilient, elastomeric materials. When coupled, theouter periphery of the female luer member conforms to the threads of theluer lock collar of the male luer member. Stiffening inserts may beencapsulated within the luer members using a process referred to asinsert molding.

The syringe tip may alternatively be coated, as disclosed in U.S. Pat.No. 4,589,871 to increase the roughness of the syringe tip. Texturing ofthe male and female portions of the luer connector to improve retentionis disclosed in U.S. Pat. Nos. 5,851,201 and 6,217,560 B1.

Various mechanical locking features have been proposed for couplingsyringe tips and needle hubs. U.S. Pat. Nos. 2,764,978 and 2,902,995disclose examples of such locking or detent features. U.S. Pat. No.4,040,421 discloses a needle hub having an internal bead that forms adepression in a boss surface on the syringe, thereby supplementing theinterference fit. U.S. Pat. Nos. 4,369,781 and 4,676,530 discloselocking members such as lock washers used to enhance the retention ofmale and female luer fittings.

SUMMARY OF THE INVENTION

The present invention provides a luer connector assembly that can beused to reliably couple a needle hub with a syringe, or to couple othermedical devices having luer slip connector portions or fittings. Amaterial is provided within a recess in a hub that will enhance thefrictional interference fit between the hub and the medical device towhich it is connected. In accordance with a preferred embodiment of theinvention, a relatively soft, resilient material is used to form anengagement surface, and is provided within a relatively rigid fitting.As the tip of a medical device is mated to the fitting, the relativelysoft material is compressed, thereby providing a more secure connectionthan would ordinarily be achieved by an interference fit between twofittings made solely from rigid or semi-rigid materials. The soft,resilient material can, for example, be incorporated in the fittingusing a two shot molding process where the fitting is first molded andthe relatively soft material is then molded on the fitting.

A needle assembly is provided in accordance with an embodiment of theinvention that reduces the chance of accidental disengagement from amedical device such as a syringe. The assembly includes a female luerfitting having a relatively rigid body including a proximal end, adistal end, a tapered interior surface and an outer surface. Apassageway extends through the body between the proximal and distalends. A cannula is connected to the distal end of the body of thefitting. The cannula is in fluid communication with the passageway. Asoft, resilient member is secured to the body of the fitting and boundsthe passageway. This member frictionally retains a male luer member onceinserted into the passageway. The soft, resilient member bounds only aportion of the passageway such that the male luer member engages boththe relatively rigid body of the female luer fitting as well as therelatively soft, resilient member.

An assembly for transferring fluid from a first medical device to asecond medical device is also provided. The first medical deviceincludes a male luer fitting having a tapered exterior surface. Thesecond medical device includes a female luer fitting having a relativelyrigid or semi-rigid body and a tapered interior surface. The male andfemale fittings are coupled such that the tapered exterior surface ofthe male luer fitting adjoins the tapered interior surface of the femaleluer fitting. The female luer fitting includes a passageway bounded bythe tapered interior surface. A relatively soft, resilient member issecured to the body of the female luer fitting and bounds thepassageway. The resilient member is deformed by the exterior surface ofthe male luer fitting, thereby increasing the reliability of theconnection of the male and female luer fittings. The male luer fittingpreferably engages both the soft, resilient member and the body of thefemale luer fitting.

A method of manufacturing a luer fitting to provide enhanced frictionalsurface(s) is further provided. The method includes the multi-shotmolding of the fitting wherein two materials are employed, one to formthe body of the fitting and the other to form at least part of arelatively soft inner surface thereof. In accordance with the method, afirst material is injected into the mold to form the body of a femaleluer fitting having an interior surface including a recess. A secondmaterial, which when cool is softer than the first material, is theninjected such that it is positioned in the recess in the interiorsurface of the female luer fitting and is coupled to the body of thefitting.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of a syringe and needle assemblyincluding a needle shield and sheath in accordance with the invention;

FIG. 2 is a perspective view of a needle assembly in accordance with theinvention;

FIG. 3 is a cross-sectional view of the needle assembly of FIG. 2.

FIG. 4 is a top perspective view showing the needle assembly with aneedle shield, coupled to a syringe, the needle shield being in the openposition;

FIG. 5 is a top perspective view thereof showing the needle shield inthe closed position;

FIG. 6 is a cross-sectional view of the needle assembly with a needleshield;

FIG. 7 is an enlarged cross-sectional view showing the needle assemblyand the shield in the closed position;

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 7;

FIG. 9 is an enlarged cross-sectional view showing the proximal end ofthe needle hub of the needle assembly;

FIG. 10 is a cross-sectional view thereof taken along line 10-10 of FIG.9;

FIG. 11 is a cross-sectional view showing a second embodiment of aneedle assembly according to the invention;

FIG. 12 is a cross-sectional view thereof taken along line 12-12 of FIG.11;

FIG. 13 is a cross-sectional view showing a needle assembly according toa third embodiment of the invention;

FIG. 14 is a cross-sectional view thereof taken along line 14-14 of FIG.13;

FIG. 15 is a top perspective view showing a needle assembly according toa fourth embodiment of the invention;

FIG. 16 is a cross-sectional view of the needle assembly of FIG. 15.

FIG. 17 is a cross-sectional view thereof taken along line 17-17 of FIG.16;

FIG. 18 is a cross-sectional view showing a needle assembly according toa fifth embodiment of the invention;

FIG. 19 is a cross-sectional view thereof taken along line 19-19 of FIG.18;

FIG. 20 is a cross-sectional view showing a needle assembly according toa sixth embodiment of the invention;

FIG. 21 is a cross-sectional view thereof taken along line 21-21 of FIG.20;

FIG. 22 is a cross-sectional view showing a needle assembly according toa seventh embodiment of the invention;

FIG. 23 is a cross-sectional view thereof taken along line 23-23 of FIG.22;

FIG. 24 is an exploded, perspective view showing a syringe and needleassembly according to an eighth embodiment of the invention;

FIG. 25 is an exploded, perspective view showing a needle assembly ofFIG. 24;

FIG. 26 is a cross-sectional view thereof showing the needle assemblyprior to its coupling to the syringe;

FIG. 27 is a cross-sectional view thereof showing the needle assemblycoupled to the syringe;

FIG. 28 is an exploded perspective view showing a needle assemblyaccording to a ninth embodiment of the invention; and

FIG. 29 is an exploded, cross-sectional view of the needle assembly ofFIG. 28.

DETAILED DESCRIPTION OF THE INVENTION

There is shown in the drawings and described below in detail preferredembodiments of the invention with the understanding that the presentdisclosure is to be considered as exemplary of the principles of theinvention and is not intended to limit the invention to the embodimentsillustrated.

A first embodiment of the invention will be described with respect toFIGS. 1-10. FIGS. 1-3 show a hypodermic needle assembly 28 according tothe invention, while FIGS. 4-6 show the assembly as coupled to asyringe. The syringe includes a barrel 20 that comprises an elongatechamber 22 for retaining fluids. A tip 24 extends from the distal end ofthe barrel. The tip 24 includes a passageway 26 for communicating withthe chamber 22, as shown in FIG. 6. The tip 24 is used to connect thesyringe to the hypodermic needle assembly 28, though it could also beused to engage other fluid transfer apparatus. It will further beappreciated that the present invention is applicable to the engagementof other types of medical devices having connector assemblies comprisedof tips and hub portions mounted over the tips. Some evacuated tubeholders, for example, have tips for accepting needle assemblies ortubing.

The syringe tip 24 is preferably frusto-conically shaped, having asmaller outside diameter at its distal end than at its proximal end. Itis often referred to as a luer tip or male luer fitting. Such tips areordinarily tapered in accordance with trade standards to allow thecoupling of parts made by different manufacturers.

The syringe barrel may be used in a hypodermic syringe assembly whichincludes the syringe barrel 20, the hypodermic needle assembly 28, apreferably resilient stopper 30 and a plunger rod 32. The stopper isslidably positioned in fluid-tight engagement inside the barrel 20. Thestopper is connected to the plunger rod 32. The plunger rod isaccessible outside of the proximal end of the syringe barrel and isprovided to move the stopper along the barrel to force fluid into or outof chamber 22 through the passageway 26. Specifically, the stopper iscapable of moving fluid from the chamber through the passageway upon itsmovement toward the distal end of the barrel, and is capable offacilitating the drawing of fluid into the chamber through the tippassageway upon its movement away from the distal end of the barrel.One-piece plunger rod/stopper assemblies can also be used.

The hypodermic needle assembly 28, as best shown in FIG. 3, includes ahub 34 having a proximal end, a distal end, and a passageway 36therethrough. A cannula 38 having a lumen 40 therethrough is connectedto the distal end of the hub preferably using an adhesive such as epoxyso that the lumen of the cannula is in fluid communication with thepassageway 36 of the hub. The cannula in this embodiment includes asharpened distal tip adapted to pierce a patient's flesh or othercutting configurations for the purpose of transferring fluid.Accordingly, movement of the stopper towards the distal end of syringebarrel 20 causes fluid to flow from the barrel through passageway 26 inthe barrel, through the hub passageway 36 and through the lumen of thecannula. Cannulas having blunt tips are also well known, and within thepurview of the present invention. Such cannulas are often used inconnection with injection sites having preslit septums. One-piece huband cannula assemblies are known to the art, and could be employed inaccordance with the invention.

This embodiment, preferably includes a housing 42 which is desirablyintegral with hub 34. The housing includes a generally cylindrical bodyhaving an open distal end that surrounds the distal end of the needlehub. A hook-like projection 44 extends from the housing and defines achannel 45 that can be used to secure a pivotable needle shield 46. Theneedle shield includes a cavity 48 for covering the cannula 38. A pivotpin 49 on the needle shield pivotably couples it to the channel 45.FIGS. 6-7 show this coupling. The needle shield may also be pivotablyconnected to the female luer fitting either directly or indirectlythrough the housing a living hinge or mechanical hinge or linkagestructure suitable for providing pivotable rotation of the needleshield. The needle shield is capable of rotating from an open positionwherein said cannula is exposed to a closed cannula protecting positionwherein at least a distal portion of the cannula is in the cavity. Oneor more deflectable projections 50 extend from the sidewall of theshield 46 into the cavity. As shown in FIGS. 6-7, the cannula 38 istrapped within the cavity by the projections 50 when the needle shieldis rotated to the closed position. The housing 42 further includes alocking element 52 to further ensure the needle shield cannot bedisplaced from the closed position. The needle shield includes a pair ofinwardly extending tabs 54 near its proximal end that ride over and thensnap behind the locking element 52. While the shield is locked in theclosed position by engaging both the cannula 38 and the locking element52, either manner of locking would provide satisfactory performance. Itshould be understood that there are a variety of ways of protectingagainst needle sticks other than pivotable needle shields.

The needle assembly 28 and the syringe are constructed so that theneedle assembly may be removably connected to the syringe tip 24.Forcing the hub towards the syringe tip will cause the frusto-conicallyshaped tip to engage the corresponding hub portion in a frictionalinterference fit which, normally, will require a certain amount of forcefor disengagement. Needle assembly hubs are commonly made of injectionmolded plastic while syringes are commonly made of injection moldedplastic or glass. The frusto-conically shaped interior of the hubpassageway and the frusto-conically-shaped exterior of the syringe tipare normally smooth, as manufactured. The frictional interference fitbetween the syringe tip and the hub accordingly may not be optimal. Thepresence of liquid may reduce the strength of the fit between the huband the syringe tip because it may act as a lubricant film.

As discussed above, various solutions have been proposed for improvingthe retention of needle assemblies and syringes. The instant inventionprovides substantial improvements over previous approaches.

In accordance with a first and preferred embodiment of the invention,the interior surface of the needle hub 34 includes a portion that iscomprised of an elastomeric material. The elastomeric material ispreferably one that is compatible with the fluids ordinarily found inbiomedical devices. Elastomers have properties that allow them to bestretched or otherwise deformed, yet return to their original positions.Materials believed to be suitable for incorporation within the hubinclude natural rubber and thermoplastic elastomers such as Santoprenerubber. The latter is an elastomeric alloy made by Advanced ElastomerSystems, and is used in the preferred embodiment described below.

Referring again to the embodiment of FIGS. 1-10, the rigid or semi-rigidhub 34 is preferably made of plastic material such as polypropylene,polyethylene or combinations thereof. Hub 34 includes a tapered interiorsurface 56 and an outer surface 58. The proximal portion of the hub isconstructed as a female luer fitting 60 and may include radiallyoutwardly projecting wings 62. The wings allow the hub to be coupled toan internally threaded receptacle concentric to a luer tip. One or morechannels 64 (as shown in FIG. 9) extend radially through the hub. Twosuch channels are provided in the first disclosed embodiment of theinvention. A generally annular recess 66 is provided in the interiorsurface of the hub. The annular recess is bounded by a wall of the bodyof the female luer fitting, as best shown in FIG. 9. Each channelextends between the interior surface of the hub, where it adjoins therecess, and the exterior hub surface. The channels 64 are diametricallyopposite from each other in this embodiment, one extending through thetop of the fitting and the other through the bottom. They mayalternatively extend through opposite sides of the fitting or elsewhere.One or more channels can be employed.

A soft, resilient member 68 is secured to the relatively rigid body ofthe female luer fitting 60. The soft, resilient member will deflect inresponse to physical pressure, such as the pressure exerted by a maleluer fitting, and will tend to return to its original shape followingdeformation. As discussed hereafter, this member and the hub 34 arepreferably manufactured using a two-shot molding process. Such a processrequires the use of compatible materials. In this preferred embodiment,the relatively soft, resilient material is SANTOPRENE rubber, which is asynthetic rubber. SANTOPRENE Rubber 171-55 and 281-55 are twothermoplastic elastomers that would be suitable for use in forming thesoft, resilient member 68. Both have a durometer hardness (A Scale (5sec)) of 55 under test method ASTM D2240. The hub 34 is preferably madefrom a thermoplastic such as polypropylene, which is harder than theSANTOPRENE rubber. When used in the manufacture of products such assyringes and needle hubs, polypropylene is generally considered to be asemi-rigid material. The soft, resilient member 68 is secured to thebody of the polypropylene female luer fitting 60 through the use of thetwo-shot molding process. As the member 68 has portions extending intothe recess 66 and channels 64, it is mechanically coupled to the femaleluer fitting 60. These elements may also be bonded together as a resultof the molding process.

The passageway 36 extending through the needle hub includes a generallyfrusto-conical portion in the area of the female luer fitting. In theembodiment of FIGS. 1-10, this portion of the passageway is bounded bythe frusto-conical surface of the soft, resilient member as well as theharder inner surface 56 of the hub. While the entire inner surface ofthe female luer fitting could be comprised of a relatively soft,resilient member, this is not preferred. It is instead preferred that amale luer tip, when coupled to the hub, engage both the relatively soft,resilient member 68 as well as the relatively harder surface of the hub.The harder surface is engaged towards the distal end of the female luerfitting 60. In this preferred embodiment, the diameter of the passageway36 is slightly smaller where it is bounded by the soft, resilient memberthan where it is bounded by the inner surface 56 of the hub. While thediameter of the passageway generally decreases in the direction of thedistal end of the hub 34, the soft, resilient member 68 projectsinwardly with respect to the inner surface 56, as shown in FIG. 3, suchthat it will frictionally engage a male luer member once positioned inthe passageway. The soft, resilient member will also preferably becompressed slightly by the male luer member. The extent to which thesoft, resilient member 68 projects inwardly with respect to the innersurface 56 may be determined by the desired coupling force between themale and female luer fittings. The user will preferably notice little orno appreciable difference in connecting the needle assembly 28 to thesyringe from conventional designs even though the removal force isgreater than in such designs.

In a preferred embodiment of the invention, the soft, resilient memberextends about 0.076 mm (0.003 inch) inwardly of the inner surface 56.Its inner diameter is accordingly about 0.152 mm (0.006 inch) less thanthe inner diameter of the inner surface 56. The inner surface of thesoft, resilient member 68 is tapered in the direction of the distal endof the hub at substantially the same angle as the inner surface 56 ofthe female luer fitting 60 in the embodiment of FIGS. 1-10. A generallyfrusto-conical passageway is accordingly provided within the female luerfitting, one portion of which is bounded by the soft, resilient memberthat will enhance the frictional retention of a male luer fitting. Itwill be appreciated that the areas of soft, resilient material and rigidor semi-rigid hub material bounding the passageway through the femaleluer fitting may be different from the embodiment of FIGS. 1-10. Asdiscussed above, the passageway is preferably constructed such that themale luer fitting engages a combination of relatively soft, resilientmaterial and the harder hub material. The male luer fitting is mostlikely comprised of a rigid or semi-rigid material such aspolypropylene.

FIGS. 9 and 10 provide substantially enlarged views of the body of thefemale luer fitting. The generally annular recess 66 is bounded by adistal shoulder 65 and a proximal shoulder 67. The shoulder 67 at theproximal end of the recess is preferably formed in such a manner that itcauses the soft, resilient member 68 to exert an increased radial forceon the male luer tip as one attempts to withdraw the male luer tip fromthe passageway 36. In other words, the retention force exerted on themale luer tip increases as one attempts to move it in the proxiamldirection until a point at which the tip is released. Referring to FIG.9, the recess 66 has a depth of about 0.254 mm (0.010 inch). Theshoulder 67 at the proximal end of the recess forms an angle with thelongitudinal axis of the hub 34 which is desirably between aboutfifty-six to sixty degrees, and preferably about fifty-eight degrees.

It is important for the soft, resilient member 68 to remain coupled tothe female luer fitting 60 and resist displacements during use. Asdiscussed above, this member is subjected to force as the male luer tipis inserted, and would also have forces exerted thereon of the male luertip is withdrawn. It is also possible for the soft, resilient member 68to be subjected to torsional forces if the male luer tip is twisted orrotated with respect to the female luer fitting. Such twisting may occurin an attempt to uncouple male and female fittings. It will occur if thehub 34 is threadably coupled to a luer lock assembly as described above.The channels 64 in the hub and the recess 66 mechanically couple thesoft, resilient member 68 and the female luer fitting 60. The diameterof the channels are slightly greater near the exterior surface of thefemale luer fitting 60 than where they adjoin the recess 66 in thispreferred embodiment. One or more longitudinal ribs 69 extend betweenthe proximal and distal shoulders 65, 67. As shown in FIG. 10, the depthof the recess exceeds the height of the ribs 69.

The needle assembly 28 may be provided to the user as shown in FIG. 1with a removable sheath 70 protecting cannula 38 when the shield 46 isin the open position. The assembly is coupled to a syringe by urging thefemale luer fitting 60 over the male luer fitting (tip 24) of thesyringe barrel. Once the needle shield 46 is pivoted back and the sheath70 is removed by disengaging it from the open distal end of housing 42of hub 34, the syringe is ready for use. FIG. 4 shows a syringe havingan attached needle assembly 28 with the shield fully rotated back andthe sheath removed. The shield may be moved to the closed position shownin FIGS. 5-7 following use. It is locked in the closed position by theprojections 50 that trap the cannula 38 and the tabs 54 that adjoin thelocking element 52 on the housing 42. It is to be appreciated that thepresent invention is applicable to assemblies having female luerfittings that may or may not be incorporated as parts of needleassemblies. Moreover, the needle assemblies may include shieldsdifferent from the shield disclosed herein or may be shieldless.

FIG. 6 shows the needle assembly 28 as coupled to a syringe having a tip24 including a standard luer taper. The soft, resilient member 68 iscompressed between the semi-rigid body of the female luer fitting 60 andthe tip 24. It is important that the recess 66 is large enough toaccommodate the compressed member so that it is substantially flush withthe inner surface 56. In addition, the distal end portion of the tip 24contacts the relatively hard inner surface 56 of the hub, preferablyforming a fluid-tight seal therewith. Although the needle assembly canbe uncoupled from the syringe, more effort is required than if both thetip 24 and the female luer fitting were both made entirely of a rigid orsemi-rigid material. The chance of accidental disengagement isaccordingly reduced. The laterally extending wings 62 at the proximalend of the needle assembly provide versatility in that they can be usedto threadably couple the needle assembly to a syringe having a threadedcollar (not shown). By causing the engagement of first the soft,resilient member 68 and then the relatively hard hub material boundingthe passageway 36 with the tip 24, the user is likely to experience twodifferent tactile sensations, the first when contact is made with thesoft, resilient member 68 and the second when the tip engages the hubmaterial. The engagement of the tip and hub material, both of which arepreferably made from a plastic material such as polypropylene, producesa reliable fluid seal. While a seal may also be provided by the soft,resilient member 68, this member is primarily used for its frictionalproperties in the preferred embodiment disclosed herein.

FIGS. 11 and 12 disclose a needle assembly 128 similar to that describedwith respect to FIGS. 1-10. The same reference numerals are accordinglyemployed to designate elements similar to those found in FIGS. 1-10. Inthis embodiment, only one channel 64 extends through the hub 34, asopposed to the two channels in the previous embodiment. The soft,resilient member 168 accordingly extends only through the one channel.It will be appreciated that various number of channels can be providedin the hub for retaining the soft, resilient member. The recess in theinner surface of the female luer fitting includes a proximally angledshoulder defining its proximal end, similar to the shoulder 67 describedabove. The recess further extends both distally and proximally beyondthe channel 64. The soft, resilient member 168 has an inner surfaceadjoining and possibly bonded to the body of the female luer fitting 60.It also extends both distally and proximally beyond the channel.

The manufacture of needle assemblies 28, 128 is preferably accomplishedby selecting compatible materials, such as polypropylene and SANTOPRENErubber, and molding them in a two-shot molding process. Various two-shotmolding techniques are known in the molding art. In accordance with onesuch technique applied to the present invention, the polypropylene isinjected, and the SANTOPRENE rubber is injected over the polypropylene.This is preferably accomplished in the same mold through the use of twoinjecting units. The polypropylene hub portion is first molded andallowed to cool for a short time. The SANTOPRENE rubber is injectionmolded over it using the second of the two injecting units. Thechannel(s) and recess provided in the hub portion provide a mechanicalconnection between the SANTOPRENE rubber and polypropylene components. Abond between these components may also be formed in this moldingprocess. The resulting product is a substantially rigid hub havingselected interior portions that are relatively soft and provideexcellent frictional properties.

The needle assembly 228 of FIGS. 13-14 includes a hub 34 that includesfour separate recesses 266 rather than the generally annular recess 66found in the embodiments of FIGS. 1-12. Four channels 64 extend throughthe female luer fitting 60 and respectively adjoin the recesses 266.Four soft, resilient members 268 are positioned in the channels andrecesses. Each such member includes a wavy inner surface bounding thepassageway 36. These members are coupled to the hub 34 using the moldingtechniques described above. The resilient members can also be secured tothe hub by an adhesive.

FIGS. 15-17 disclose a fourth embodiment of the invention. In thisembodiment, the needle assembly 328 includes a pair of opposing channels364. The soft, resilient member 368 includes a generally annular orfrustoconical exterior portion 370 that adjoins the exterior surface ofthe body of the female luer fitting 60. Two radially inwardly extendingportions 372 of the soft, resilient member 368 extend through thechannels 364 and into the passageway 36 to provide frictional engagementsurfaces for retention of a male luer fitting. As in the previousembodiments, the inwardly extending portions 372 of the soft, resilientmember 368 are displaced radially outwardly by the male luer fitting(not shown) such that they become substantially flush with the innersurface 56 of the female luer fitting. In addition, the male luerfitting engages and preferably forms a fluid tight seal with the innersurface 56 distal to the soft, resilient member 368. As in theembodiment of FIGS. 1-12, it is preferred that the hub and resilientmembers be formed by a two-shot molding process. However, resilientmember 368 may be made as a separate member and slipped over the hub into the position illustrated with or without an adhesive to hold theresilient member to the hub.

FIGS. 18-19 show a fifth embodiment of the invention. It is similar tothe embodiment of FIGS. 15-17 in that the exterior surface of the femaleluer fitting 60 is defined in part by the exterior surface of a soft,resilient member 468. Four channels 64 extend through the female luerfitting. Portions of the soft, resilient member 468 extend through thechannels and into the passageway 36. Unlike the first three embodiments,where the recesses 66 in the interior surface of the body of the femaleluer fitting extend beyond the channel openings, both distally andproximally, the recesses and channels 64 of this needle assembly 428 arecoextensive. It is also similar to the fourth embodiment in thisrespect. The recesses accordingly have not been designated with separatereference numerals in either the fourth or fifth embodiments. In all ofthe embodiments, the recesses allow for the radial displacement of thesoft, resilient member when a male luer fitting is within thepassageway, allowing this member to become substantially flush with theinner surface 56 of the hub. In the embodiment of FIGS. 18-19, agenerally annular recess 476 extends within the exterior surface of thefemale luer fitting. The channels 64 extend between the recess 476 andthe inner surface 56 of the hub. Insertion of a male luer fitting into apassageway 36 causes the radial displacement of the portions of thesoft, resilient member 468 that project into the passageway. The maleluer fitting will be engaged by both the inwardly projecting portions ofthe soft, resilient member and the relatively hard inner surface 56 ofthe hub. It preferably forms a fluid tight seal with the inner surfaceof the hub distal to the area of engagement with the soft, resilientmember 468.

FIGS. 20-21 show a needle assembly 528 according to a sixth embodimentof the invention. In this embodiment, recesses 566 and 576 extendingbeyond the inner and outer openings of the channels 564 are provided inthe inner surface 56 and the outer surface of the hub, respectively. Theinner recesses 566 include generally rectangular outlines while theouter recess is generally annular or frustoconical. It will beappreciated that the inner recesses 566 could be formed as a generallyannular recess as well, similar to that of the first describedembodiment. The inner surfaces of the portions of the soft, resilientmember 568 are shown as wavey. They could, however, generally conform tothe shape of the inner surface 56 of the hub in the area of the femaleluer fitting 60, which is frustoconical. As in the previously describedembodiments, a male luer fitting positioned in the passageway 36 willengage both the soft, resilient member 568 and the relatively hard innersurface 56 of the hub. It will displace the portions of the soft,resilient member 568 that extend in the passageway 36 so that they aresubstantially flush with the inner surface 56.

A needle assembly 628 according to a seventh embodiment of the inventionis shown in FIGS. 22-23. This embodiment is substantially the same asthat shown in FIGS. 18-19, only the inner surfaces of the soft,resilient member 668 are generally convex. When compressed by a maleluer fitting, the portion of the resilient member 668 projecting intothe passageway will be displaced into the channel/recess 664 from whichit extends.

An eighth embodiment of the invention is shown in FIGS. 24-27. In thisembodiment, one or more elastomeric plugs 768 are coupled to the hub 734of a needle assembly 728. The hub 734 includes one or more radiallyextending channels 764 extending between the inner and outer surfacesthereof. Each plug includes a shaft portion 770 that extends through achannel 764 and preferably an enlarged head portion 772 integral withthe end of the shaft portion contacting the outer surface of the hub. Ashead portion is larger in diameter than the channel, the plug isrestrained from falling into the hub. Channels 764 and shaft portions770 are tapered to be larger at the inside surfaces of the hub than atthe outside surface, to prevent plugs 768 from being pushed out of thechannels when the hub engages a male luer fitting. The plug can bemechanically coupled to the hub or multi-shot molded with the hub withor without the head portions. If mechanically coupled, only the innerportion must be of elastomeric material. The remainder of the plug canbe comprised of other materials, such as a rigid or semi-rigid plasticmaterial. The plug or portion thereof adjoining the passage 736 shouldbe non-reactive with the fluids that are likely to be delivered by thesyringe or other medical device.

As shown in FIG. 28, the inner head portion 772 of the plug 768 deformswhen the tip 24 of the syringe is inserted into the passageway 736 ofthe needle hub 734. The retention force between the needle hub 734 andtip 24 is accordingly superior to that provided by an interference fitbetween these parts in the absence of the plug. A substantiallyfluid-tight coupling of the needle hub and tip is also provided despitethe presence of the elastomeric material. This is accomplished throughthe use of a relatively small, readily compressible head portion that,when compressed between the needle hub and tip, creates substantially nogaps of such size that would compromise the seal between these elements.It will be noted that a portion of the inner head portion 772 of theplug 768 overlies the frustoconical inner surface 756 of the hub 734.This is in contrast to the above-described embodiments where no portionsof the soft, resilient members overlie this surface. It is preferable tohave no portion of the soft, resilient member(s) directly on the innerhub surface, and to provide an area or areas within the inner hubsurface for these member(s) to move when compressed by the male luerfitting. As discussed above, it is preferable that the inner surface ofsoft, resilient member becomes flush with the inner hub surface when amale luer fitting is within the passageway so that both the inner hubsurface and the inner surface of the resilient member contact the maleluer fitting to form a seal. If the resilient member is too large or therecess not adequate to accept the resilient member when it iscompressed, or if resilient material is trapped between the surface ofthe hub and the outer surface of the male luer fitting, an effectiveseal will not form between the hub and the male luer fitting.

FIGS. 28-29 show a ninth embodiment of the invention wherein the innersurface of the needle hub 834 includes an annular groove 866 borderingthe passageway 836. An elastomeric ring 868 is insertable into thepassageway through the proximal opening in the needle hub, and can bepositioned at least partially within the groove 866. Insertion of a luertip within the passageway causes the ring 868 to be compressed, therebyenhancing retention as well as providing a fluid seal. The ring can becompressed sufficiently by a male luer fitting such that the ring issubstantially contained by the groove. The groove should be large enoughor have channels to allow ring 868 to be compressed until it issubstantially flush with the inner surface of the hub.

It will be appreciated that the principles of the invention can beapplied to female luer fittings used in connection with various medicaldevices, and that the devices shown and described herein arerepresentative of the ways the invention can be employed.

What is claimed is:
 1. A method of manufacturing a needle assembly comprising: forming a body of a female luer fitting from a first material, the body including a distal end, a proximal end, a passageway extending between said proximal and distal ends, said passageway having a frustoconical portion, and a recess extending within said body and adjoining said frustoconical portion of said passageway; forming at least one channel through a wall of said body of said female luer fitting, said at least one channel extending between said recess and an exterior surface of said body; and injecting a resilient second material that is softer than the first material into said channel formed in said female luer fitting such that a portion of said second material extends into said passageway.
 2. The method of claim 1 further including the step of securing a cannula to said distal end of said female luer fitting.
 3. The method of claim 1 wherein said resilient second material is a thermoplastic elastomer.
 4. The method of claim 3 wherein said resilient second material is injected while said first material is warm.
 5. The method of claim 1, wherein said first material is a thermoplastic material.
 6. The method of claim 5 wherein said thermoplastic material is selected from the group consisting of polypropylene, polyethylene and combinations thereof.
 7. The method of claim 1 wherein said recess extending both distally and proximally beyond said resilient second material. 